Notch strength of ductile materials with different work-hardening behaviors

Additive-manufactured (AMed) alloys and high-entropy alloys (HEAs) have been extensively developed in recent years due to their excellent properties. Assessing the notch properties such as the notch strength, however, is of importance for the engineering applications of these emerging structural materials. In this work, we studied the notch tensile properties of an AMed steel (17-4 PH), two ductile HEAs (HfNbTaTiZr and TiVNbTa), and a pure Cu, with the focus on the effect of work-hardening behavior on the notch strength. We found that, surprisingly, the AMed steel and the two ductile HEAs with distinctive tensile properties show similar notch strength ratio (NSR) i.e., the ratio of notch strength to ultimate tensile strength, and higher than the NSR of pure Cu. Further studies by finite element analysis (FEA) of eight different materials with designed tensile properties reveal that comparing with the strength, the work-hardening behavior affects the NSR much more significantly. The results demonstrate that for ductile materials, tailoring their work-hardening behavior is of significance for the loading capacity of samples or components with the existence of external defects like notches.